Ceramic multi-layer superstructures, in particular, those with electrically conductive structures implemented in metallization layers, can be used as dielectric carrier substrates with an integrated wiring structure. It is also possible to use functional ceramics in a ceramic multi-layer structure, so that component functions can be integrated into the multi-layer structure in connection with electrode structures. It is also possible to realize complete electrical circuits in the form of components integrated into a multi-layer structure.
The overall objective in the development of electrical components is to create highly miniaturized structures and components that work reliably and that can be easily produced. One problem with ceramic components results from the fact that ceramic green material and particularly ceramic green films compress during sintering and therefore exhibit shrinkage, which can equal, e.g., 20 to 50 volume percent and more. Due to the volume shrinkage, the geometrical relationships of all of the structures realized in and on the ceramic and particularly those of electrically conductive structures change. One objective is therefore to configure the volume shrinkage during sintering in such a way that it takes place essentially in a dimension vertical to the plane of the multi-layer structure and that, within the layer plane, the structures given in the green film are maintained without excessive changes after sintering.
From DE 10145363 A1, a multi-layer ceramic is known in which component functions are implemented. A lateral distortion of the multi-layer structure is here prevented by two measures. An increased proportion of sintering agent is added to the uppermost layer of the multi-layer structure and the multi-layer structure is then deformed with a constraining layer that exhibits no structural conversion at the sintering temperatures used for the component and therefore reduces the distortion of the multi-layer structure associated with the constraining layer. The elevated component of sintering agents in the uppermost layer of the multi-layer structure provides good adhesion of the constraining layer in that the sintering agent diffuses into the adjacent layers. This has the disadvantage, however, that a) the constraining layer must be removed after sintering, b) the sintering agent also diffuses into the functional ceramic, changes the composition of this ceramic, and influences the electrical operation in a disadvantageous and an at least uncontrollable way, and also that c) external metal contacts must still be deposited at a later time or are contaminated at least with the residues of the constraining layer.
From EP 1453091 A1, a dielectric ceramic substrate with a multi-layer structure is known which comprises a combination from a glass-ceramic layer in the interior of the multi-layer structure and an external glass layer remaining in the glass state.